Donkeys are very minimalistic animals -- that is to say, they need very little of anything and everything. Little food, little water, little grooming, little footwork.
The worst thing we ever did with our donkey was to overfeed him. Donkeys are desert animals and easily suffer serious health issues from overweightness (? Is that even a word? LOL) A lush field is bad news. Bedding? For what? Don't lock them in a stall. Let them have free access to a three sided shelter and they're good to go. Honestly - instead of spending oodles and oodles of time on physical care, spend it instead on just time with them. They are very intelligent, very loyal beasts and you will be richly rewarded if you earn their respect, trust and keep their curiousity appeased.